The present invention relates to a sheets aligner for use in a sheet fed printing press, and more particularly to a sheets aligner which stacks on a pallet a large number of sheets fed to a sheet feeder of the sheet-fed printing press, the sheets aligner having front lays which stop the sheets to align their edges.
The sheet feeder of the sheet-fed printing press is provided with a sheet stacking board for stacking sheets for printing. The sheets stacked are sucked one by one from ones positioned at the upper layer by means of a suction device and then are sent out onto a feed board. Thereafter, they are delivered to a printing unit at which a required printing is implemented thereto. In this instance, the sheets are heaped up on a pallet in a different place and then conveyed to the sheet stacking board by means of a lift etc. If edges of the sheets stacked on the pallet are not aligned, a mis-registration of the printing will be caused, resulting in occurence of waste sheets. For this reason, a sheet aligner which stacks the sheets while aligning their edges is provided in a place where the sheets are heaped up on the pallet.
The recent automatic printing press has a sheet alignment and turn over station therein. Sheets which have been packaged, e.g., every several hundred thereof and stored in a warehouse are conveyed onto a lift table of the station. Thus, the sheets conveyed is delivered to the sheet aligner from the lift table, and then is delivered onto the pallet while they are unpacked and is subjected to alignment. In addition, when printing is required to be implemented on the back sides of the sheets which have been printed at the printing unit, the sheets stacked on the sheet stacking board are conveyed to the sheet alignment and turn over station by means of a conveyor while the sheets are stacked on the pallet. The sheets conveyed are turned over by means of a turn over machine provided in association with the sheet aligner, and then are delivered from the lift table to the sheet aligner, at which they are subjected to the alignment.
FIGS. 1 and 2 are perspective views schematically illustrating a conventional sheet aligner. FIG. 1 shows the condition that the pallet has been delivered to the sheet aligner and FIG. 2 shows the condition that sheets are stacked on the pallet. As seen from these figures, on an L-shaped base 1, a frame body 2 which is similarly L-shaped in plane is disposed with its lower end being rotatably supported. Within the frame body 2, a vertically movable table 3 which is driven by a drive unit to move upwardly and downwardly is provided. The frame body 2 is configured as follows. The frame body 2 is driven by a motor etc. so that it rotates about the lower end corner portion to selectively take a posture at which the movable table 3 shown in FIG. 1 is horizontally placed or other posture shown in FIG. 2 at which edges 2c and 2d of two sides 2a and 2b of the frame body 2 rises by the same heights from the first-mentioned position, that is, the frame body 2 is inclined. On the respective sides 2a and 2b of the frame body 2, a plurality of front lays are fixed vertically and parallel to each other, thereby the movement of the sheets movement is restricted.
In the sheets aligner 5 thus configured, a pallet 6 is delivered in a direction indicated by an arrow A perpendicular to the side 2a of the frame body 2 from a lift table (not shown) disposed adjacent to the frame body 2 onto the movable table 3 placed in the horizontal condition shown in FIG. 1. After the pallet has been delivered, the frame body 2 is inclined as shown in FIG. 2. During this time, the sheets which have been conveyed onto the lift table are delivered onto the pallet 6 every predetermined number by means of human power or a sheet conveying device recently being developed. The, these sheets are stacked as indicated by reference numeral 7 on the movable table 3 through the pallet 6, and the movable table 3 lowers depending upon the stacking amount of the sheets 7.
Thus, the supply of the pallet 6 onto the movable table 3 and the supply of the sheets 7 onto the pallet 6 are stopped by the contact of the pallet 6 and the sheets 7 with the front lays 4. Then, a vibrating plate (not shown) gives a vibration to the edges of the sheets 7 which are in contact collectively with the front lays 4, whereby the sheet edges are aligned.
However, such a conventional sheets aligner has the problem in the handling when the sheet size is changed. Namely, as shown in a schematic plan view of the sheet aligner in FIG. 3, the sheets stacked on the pallet 6 change between the maximum size sheet labeled 7A and the minimum size sheet labeled 7B. Corresponding two sides of the sheets 7A and 7B and the pallet 6 are aligned by the front lays 4 provided on the two sides 2a and 2b of the frame body 2 irrespective of the sheet size. Accordingly, when the pallet 6 provided in conformity with the sheet 7A of maximum size is used commonly to a sheet having a size smaller than the maximum size, for example, the sheet 7B of minimum size, blank portions indicated by symbols S.sub.1 and S.sub.2 are formed between two sides opposite to the front lays 4 of the sheet 7B and two sides of the pallet 6. The pallet 6 on which the sheets 7 are stacked is delivered to the sheet feeder of the printing press with it being positioned so that the sheets 7 are fed to the printing unit ordinarily in direction indicated by an arrow B in FIG. 3. When the minimum size sheets 7B are delivered, since the center of the paper 7B greatly deviates to the left with respect to the machine width center, the pallet 6 on which the sheets 7B are placed must be greatly moved in a left direction approximately by S.sub.1 /.sub.2 on the printing press as compared with the case of the maximum size sheet, resulting in the possibility that the pallet 6 can not be moved because the pallet 6 is in contact with the frame body 2. Accordingly, when applied to such a center reference type printing press, it has been impossible to use the pallet 6 commonly to various sheet sizes. Another attempt is made to commonly use a smaller sized pallet 6. In this case, sheets having a size larger than that of such a pallet such as the maximum size sheets 7A will be loaded with the pallet 6 being drawn from the sheet edges during sheet stacking. This results in the inconveniences that not only the pallet 6 is difficult to be conveyed but also the sheet edges protruded from the pallet 6 become stained or damaged. Further, in the case where the pallet 6 is used commonly to various sheet sizes, if the sheet size is small at the time when the printing is applied to the back sides of the above-mentioned sheets with they being turned over, there occurs the problem that the edges of the sheets which have been turned over and loaded do not fall within a range of movement of a side register device provided in the printing press.
Since the pallet 6 cannot be used commonly to various sheet sizes for the reason stated above, many kinds of pallets 6 corresponding to the sheet sizes must be prepared, giving rise to the problems that not only the work becomes troublesome with a result of increasing the cost required therefor, but also control becomes difficult during conveying or at various processes such as a printing process, unless kinds of the pallets 6 are unified at the above-mentioned automatic factory.